Computer Networks 4

Global Internet

collection of independently operated networks that cooperate to exchange traffic

Link State routing

each router discovers its neighbors and the cost to reach them, flood the information though the network and build a complete topology map

Interdomain routing

handles routing between AS. Governed by administrative policy, not just shortest path; scalability and policy control are more important than optimal path

Intradomain routing

routing within a single AS, uses link-state routing and supports hierarchical routing

Autonomous Systems

collection of IP networks and routers operated under the control of a single administrative entity

border router

router that is forwarding packets between different autonomous systems

hierarchy

information is hidden from some nodes in the network, hindering their ability to make perfect decisions, saves the nodes from having global knowledge about the network

Border Gateway Protocol (BGP)

primary interdomain routing protocol of the Internet, makes no assumptions about how ASses are interconnected, uses path-vector routing

local traffic in AS

traffic that originates at or terminates on nodes within an AS

transist traffic in AS

traffic that passes through an AS to the other one

reachability

infroms if node can be reach given network through this AS

AS categories

Stub AS, Multihomed Stub AS, Transit AS

Stub AS

AS that only carries a local traffic

Multihomed Stub AS

AS has connections to more than one other AS but that refuses to carry transit traffic

Transit AS

AS has connections to more than one other AS and that is designed to carry both transit and local traffic

Multicast model

model based on multicast groups, where each group has its own IP, multicast address. The hosts that are members of a group receive copies of any packets sent to that group’s multicast address

Distance Vector Multicast Routing Protocol (DVMRP)

mechanism that allows a packet to be forwarded to all the networks on the internet, additionally we refine this mechanism so that it prunes back networks that do not have hosts that belong to the multicast group

Protocol Independent Multicast (PIM)

divides the problem space into sparse mode and dense mode, where sparse and dense refer to the proportion of routers that will want the multicas

Dense Mode

many receivers

Sparse Mode

few receivers

Multiprotocol Label Switching (MLP)

combines some of the properties of virtual circuits with the flexibility and robustness of datagrams, uses short labels instead of IP addresses for forwarding packets

Virtual Private Network (VPN)

allows secure and isolated communication over shared infrastructure between your device and the Internet

mobile IP

mobile host is assumed to have a permanent IP address, called its home address, which has a network prefix equal to that of its home network